PHYLOGENETIC RECONSTRUCTION AND EVOLUTIONARY ANALYSIS OF LABEONINAE (CYPRINIDAE) BASED ON COI GENE ANALYSES

Abstract

Among the six sub-family Cyprinidae families of fishes the Labeonie is the most popular which consists of 473 valid species which 71 species are available during last 10 years. In Bangladesh context, Labeonine consists of most of the economically important species. The Labeo lineage is the second most important group of cyprinid fishes after the Barbiinae. In previous research it was found that the taxa of Labeoninae showed complex phylogenetic relationship. Therefore, in this study the evolutionary trend and phylogenetic relationship of this sub-family were studied. Five taxa of Labeo genus and two taxa of other sub-family were collected from the Atrai river of Dinajpur, Bangladesh. DNA extraction, PCR amplification with fFish barcode COI gene primer pairs, purification of PCR products and DNA sequencing were done in the Fish Biotechnology laboratory of National Institute of Biotechnology (NIB). The raw nucleotide sequence data of COI gene were aligned and truncated using DAMBE software and blasted at NCBI genebank database and finally submitted to the NCBI nucleotide database. At the same time 10 COI nucleotide sequenes of similar speceis were retrived from NCBI nucletide databases. Finally a data set of 17 nucleotide of cyprinidae taxa and 1 outgroup taxa, Clarias batruchus were analyzed using MEGA (Ver. 7.0) software. A total of 651 sites in studied COI nucleotide sequences were identified where the conserved sites were higher (557 to 591) than the variable sites (45 to 76), The nucleotide composition was for (A):15.8, (T):24.4, (C): 26.8, and (32.9) with higher GC content (59%). The transition/transversion bias among the COI nucleotide sequences of studied Labeonine taxa was found 0.51. The transitional substitution was lower (33.788) than the tarnsversional substitution (66.212). Lower levels of genetic distances between the taxa (ranged from 0.000 to 0.043) were found. In phylogenetic trees the taxa were found to formed two distinct clades where the taxa of the genus Labeo of India formed Clade 1, and the taxa of the genus Labeo of Bangladesh formed Clade 2 . Sequenced taxa of the cyprinidae other than Labeo genus such as E. danricus and C. chagunio did not formed cluster with the taxa of Labeo genus. The time tree showed that nucleotide divergence occurred among the taxa about 0.015 million years ago (MYA). Based on the COI nucleotide sequences the study concluded that the Bangladeshi Labeonie taxa maintains a highly conserved nature with unique identity in consideration to the same taxa of the neighboring country India. To maintain the pure broodstocks of these taxa a detail study by involving more number of individuals and genes are recommended.